HttpClient使用详解

来源：互联网发布：mac转换铃声编辑：程序博客网时间：2024/06/01 22:21

更详细教程：

http://www.yeetrack.com/?p=779

http://www.cnblogs.com/chenying99/p/3735282.html

配置访问https, 信任所有：

直接上代码，做一个创建client的工具类
public static CloseableHttpClient createSSLClientDefault(){
try {
SSLContext sslContext = new SSLContextBuilder().loadTrustMaterial(null, new TrustStrategy() {
//信任所有
public boolean isTrusted(X509Certificate[] chain,
String authType) throws CertificateException {
return true;
}
}).build();
SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(sslContext);
return HttpClients.custom().setSSLSocketFactory(sslsf).build();
} catch (KeyManagementException e) {
e.printStackTrace();
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
} catch (KeyStoreException e) {
e.printStackTrace();
}
return HttpClients.createDefault();
}

原文地址：http://blog.csdn.net/wangpeng047/article/details/19624529

Http协议的重要性相信不用我多说了，HttpClient相比传统JDK自带的URLConnection，增加了易用性和灵活性（具体区别，日后我们再讨论），它不仅是客户端发送Http请求变得容易，而且也方便了开发人员测试接口（基于Http协议的），即提高了开发的效率，也方便提高代码的健壮性。因此熟练掌握HttpClient是很重要的必修内容，掌握HttpClient后，相信对于Http协议的了解会更加深入。

一、简介

HttpClient是Apache Jakarta Common下的子项目，用来提供高效的、最新的、功能丰富的支持HTTP协议的客户端编程工具包，并且它支持HTTP协议最新的版本和建议。HttpClient已经应用在很多的项目中，比如Apache Jakarta上很著名的另外两个开源项目Cactus和HTMLUnit都使用了HttpClient。

下载地址: http://hc.apache.org/downloads.cgi

二、特性

1. 基于标准、纯净的java语言。实现了Http1.0和Http1.1

2. 以可扩展的面向对象的结构实现了Http全部的方法（GET, POST, PUT, DELETE, HEAD, OPTIONS, and TRACE）。

3. 支持HTTPS协议。

4. 通过Http代理建立透明的连接。

5. 利用CONNECT方法通过Http代理建立隧道的https连接。

6. Basic, Digest, NTLMv1, NTLMv2, NTLM2 Session, SNPNEGO/Kerberos认证方案。

7. 插件式的自定义认证方案。

8. 便携可靠的套接字工厂使它更容易的使用第三方解决方案。

9. 连接管理器支持多线程应用。支持设置最大连接数，同时支持设置每个主机的最大连接数，发现并关闭过期的连接。

10. 自动处理Set-Cookie中的Cookie。

11. 插件式的自定义Cookie策略。

12. Request的输出流可以避免流中内容直接缓冲到socket服务器。

13. Response的输入流可以有效的从socket服务器直接读取相应内容。

14. 在http1.0和http1.1中利用KeepAlive保持持久连接。

15. 直接获取服务器发送的response code和 headers。

16. 设置连接超时的能力。

17. 实验性的支持http1.1 response caching。

18. 源代码基于Apache License 可免费获取。

三、使用方法

使用HttpClient发送请求、接收响应很简单，一般需要如下几步即可。

1. 创建HttpClient对象。

2. 创建请求方法的实例，并指定请求URL。如果需要发送GET请求，创建HttpGet对象；如果需要发送POST请求，创建HttpPost对象。

3. 如果需要发送请求参数，可调用HttpGet、HttpPost共同的setParams(HetpParams params)方法来添加请求参数；对于HttpPost对象而言，也可调用setEntity(HttpEntity entity)方法来设置请求参数。

4. 调用HttpClient对象的execute(HttpUriRequest request)发送请求，该方法返回一个HttpResponse。

5. 调用HttpResponse的getAllHeaders()、getHeaders(String name)等方法可获取服务器的响应头；调用HttpResponse的getEntity()方法可获取HttpEntity对象，该对象包装了服务器的响应内容。程序可通过该对象获取服务器的响应内容。

6. 释放连接。无论执行方法是否成功，都必须释放连接

四、实例

[java] view plaincopyprint?

package com.test;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.security.KeyManagementException;
import java.security.KeyStore;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.cert.CertificateException;
import java.util.ArrayList;
import java.util.List;
import javax.net.ssl.SSLContext;
import org.apache.http.HttpEntity;
import org.apache.http.NameValuePair;
import org.apache.http.ParseException;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
import org.apache.http.conn.ssl.SSLContexts;
import org.apache.http.conn.ssl.TrustSelfSignedStrategy;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.mime.MultipartEntityBuilder;
import org.apache.http.entity.mime.content.FileBody;
import org.apache.http.entity.mime.content.StringBody;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;
import org.junit.Test;
public class HttpClientTest {
@Test
public void jUnitTest() {
get();
}
/**
* HttpClient连接SSL
*/
public void ssl() {
CloseableHttpClient httpclient = null;
try {
KeyStore trustStore = KeyStore.getInstance(KeyStore.getDefaultType());
FileInputStream instream = new FileInputStream(new File("d:\\tomcat.keystore"));
try {
// 加载keyStore d:\\tomcat.keystore
trustStore.load(instream, "123456".toCharArray());
} catch (CertificateException e) {
e.printStackTrace();
} finally {
try {
instream.close();
} catch (Exception ignore) {
}
}
// 相信自己的CA和所有自签名的证书
SSLContext sslcontext = SSLContexts.custom().loadTrustMaterial(trustStore,new TrustSelfSignedStrategy()).build();
// 只允许使用TLSv1协议
SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(sslcontext, new String[] {"TLSv1" },null,
SSLConnectionSocketFactory.BROWSER_COMPATIBLE_HOSTNAME_VERIFIER);
httpclient = HttpClients.custom().setSSLSocketFactory(sslsf).build();
// 创建http请求(get方式)
HttpGet httpget = new HttpGet("https://localhost:8443/myDemo/Ajax/serivceJ.action");
System.out.println("executing request" + httpget.getRequestLine());
CloseableHttpResponse response = httpclient.execute(httpget);
try {
HttpEntity entity = response.getEntity();
System.out.println("----------------------------------------");
System.out.println(response.getStatusLine());
if (entity != null) {
System.out.println("Response content length: " + entity.getContentLength());
System.out.println(EntityUtils.toString(entity));
EntityUtils.consume(entity);
}
} finally {
response.close();
}
} catch (ParseException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (KeyManagementException e) {
e.printStackTrace();
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
} catch (KeyStoreException e) {
e.printStackTrace();
} finally {
if (httpclient !=null) {
try {
httpclient.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
/**
* post方式提交表单（模拟用户登录请求）
*/
public void postForm() {
// 创建默认的httpClient实例.
CloseableHttpClient httpclient = HttpClients.createDefault();
// 创建httppost
HttpPost httppost = new HttpPost("http://localhost:8080/myDemo/Ajax/serivceJ.action");
// 创建参数队列
List<namevaluepair> formparams = new ArrayList<namevaluepair>();
formparams.add(new BasicNameValuePair("username","admin"));
formparams.add(new BasicNameValuePair("password","123456"));
UrlEncodedFormEntity uefEntity;
try {
uefEntity = new UrlEncodedFormEntity(formparams,"UTF-8");
httppost.setEntity(uefEntity);
System.out.println("executing request " + httppost.getURI());
CloseableHttpResponse response = httpclient.execute(httppost);
try {
HttpEntity entity = response.getEntity();
if (entity !=null) {
System.out.println("--------------------------------------");
System.out.println("Response content: " + EntityUtils.toString(entity,"UTF-8"));
System.out.println("--------------------------------------");
}
} finally {
response.close();
}
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (UnsupportedEncodingException e1) {
e1.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
// 关闭连接,释放资源
try {
httpclient.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
/**
* 发送 post请求访问本地应用并根据传递参数不同返回不同结果
*/
public void post() {
// 创建默认的httpClient实例.
CloseableHttpClient httpclient = HttpClients.createDefault();
// 创建httppost
HttpPost httppost = new HttpPost("http://localhost:8080/myDemo/Ajax/serivceJ.action");
// 创建参数队列
List<namevaluepair> formparams = new ArrayList<namevaluepair>();
formparams.add(new BasicNameValuePair("type","house"));
UrlEncodedFormEntity uefEntity;
try {
uefEntity = new UrlEncodedFormEntity(formparams,"UTF-8");
httppost.setEntity(uefEntity);
System.out.println("executing request " + httppost.getURI());
CloseableHttpResponse response = httpclient.execute(httppost);
try {
HttpEntity entity = response.getEntity();
if (entity != null) {
System.out.println("--------------------------------------");
System.out.println("Response content: " + EntityUtils.toString(entity,"UTF-8"));
System.out.println("--------------------------------------");
}
} finally {
response.close();
}
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (UnsupportedEncodingException e1) {
e1.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
// 关闭连接,释放资源
try {
httpclient.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
/**
* 发送 get请求
*/
public void get() {
CloseableHttpClient httpclient = HttpClients.createDefault();
try {
// 创建httpget.
HttpGet httpget = new HttpGet("http://www.baidu.com/");
System.out.println("executing request " + httpget.getURI());
// 执行get请求.
CloseableHttpResponse response = httpclient.execute(httpget);
try {
// 获取响应实体
HttpEntity entity = response.getEntity();
System.out.println("--------------------------------------");
// 打印响应状态
System.out.println(response.getStatusLine());
if (entity !=null) {
// 打印响应内容长度
System.out.println("Response content length: " + entity.getContentLength());
// 打印响应内容
System.out.println("Response content: " + EntityUtils.toString(entity));
}
System.out.println("------------------------------------");
} finally {
response.close();
}
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (ParseException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
// 关闭连接,释放资源
try {
httpclient.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
/**
* 上传文件
*/
public void upload() {
CloseableHttpClient httpclient = HttpClients.createDefault();
try {
HttpPost httppost = new HttpPost("http://localhost:8080/myDemo/Ajax/serivceFile.action");
FileBody bin = new FileBody(new File("F:\\image\\sendpix0.jpg"));
StringBody comment = new StringBody("A binary file of some kind", ContentType.TEXT_PLAIN);
HttpEntity reqEntity = MultipartEntityBuilder.create().addPart("bin", bin).addPart("comment", comment).build();
httppost.setEntity(reqEntity);
System.out.println("executing request " + httppost.getRequestLine());
CloseableHttpResponse response = httpclient.execute(httppost);
try {
System.out.println("----------------------------------------");
System.out.println(response.getStatusLine());
HttpEntity resEntity = response.getEntity();
if (resEntity != null) {
System.out.println("Response content length: " + resEntity.getContentLength());
}
EntityUtils.consume(resEntity);
} finally {
response.close();
}
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
httpclient.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}</namevaluepair></namevaluepair></namevaluepair></namevaluepair>

package com.test;import java.io.File;import java.io.FileInputStream;import java.io.IOException;import java.io.UnsupportedEncodingException;import java.security.KeyManagementException;import java.security.KeyStore;import java.security.KeyStoreException;import java.security.NoSuchAlgorithmException;import java.security.cert.CertificateException;import java.util.ArrayList;import java.util.List;import javax.net.ssl.SSLContext;import org.apache.http.HttpEntity;import org.apache.http.NameValuePair;import org.apache.http.ParseException;import org.apache.http.client.ClientProtocolException;import org.apache.http.client.entity.UrlEncodedFormEntity;import org.apache.http.client.methods.CloseableHttpResponse;import org.apache.http.client.methods.HttpGet;import org.apache.http.client.methods.HttpPost;import org.apache.http.conn.ssl.SSLConnectionSocketFactory;import org.apache.http.conn.ssl.SSLContexts;import org.apache.http.conn.ssl.TrustSelfSignedStrategy;import org.apache.http.entity.ContentType;import org.apache.http.entity.mime.MultipartEntityBuilder;import org.apache.http.entity.mime.content.FileBody;import org.apache.http.entity.mime.content.StringBody;import org.apache.http.impl.client.CloseableHttpClient;import org.apache.http.impl.client.HttpClients;import org.apache.http.message.BasicNameValuePair;import org.apache.http.util.EntityUtils;import org.junit.Test;public class HttpClientTest {@Testpublic void jUnitTest() {get();}/** * HttpClient连接SSL */public void ssl() {CloseableHttpClient httpclient = null;try {KeyStore trustStore = KeyStore.getInstance(KeyStore.getDefaultType());FileInputStream instream = new FileInputStream(new File("d:\\tomcat.keystore"));try {// 加载keyStore d:\\tomcat.keystore  trustStore.load(instream, "123456".toCharArray());} catch (CertificateException e) {e.printStackTrace();} finally {try {instream.close();} catch (Exception ignore) {}}// 相信自己的CA和所有自签名的证书SSLContext sslcontext = SSLContexts.custom().loadTrustMaterial(trustStore, new TrustSelfSignedStrategy()).build();// 只允许使用TLSv1协议SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(sslcontext, new String[] { "TLSv1" }, null,SSLConnectionSocketFactory.BROWSER_COMPATIBLE_HOSTNAME_VERIFIER);httpclient = HttpClients.custom().setSSLSocketFactory(sslsf).build();// 创建http请求(get方式)HttpGet httpget = new HttpGet("https://localhost:8443/myDemo/Ajax/serivceJ.action");System.out.println("executing request" + httpget.getRequestLine());CloseableHttpResponse response = httpclient.execute(httpget);try {HttpEntity entity = response.getEntity();System.out.println("----------------------------------------");System.out.println(response.getStatusLine());if (entity != null) {System.out.println("Response content length: " + entity.getContentLength());System.out.println(EntityUtils.toString(entity));EntityUtils.consume(entity);}} finally {response.close();}} catch (ParseException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();} catch (KeyManagementException e) {e.printStackTrace();} catch (NoSuchAlgorithmException e) {e.printStackTrace();} catch (KeyStoreException e) {e.printStackTrace();} finally {if (httpclient != null) {try {httpclient.close();} catch (IOException e) {e.printStackTrace();}}}}/** * post方式提交表单（模拟用户登录请求） */public void postForm() {// 创建默认的httpClient实例.  CloseableHttpClient httpclient = HttpClients.createDefault();// 创建httppost  HttpPost httppost = new HttpPost("http://localhost:8080/myDemo/Ajax/serivceJ.action");// 创建参数队列  List<namevaluepair> formparams = new ArrayList<namevaluepair>();formparams.add(new BasicNameValuePair("username", "admin"));formparams.add(new BasicNameValuePair("password", "123456"));UrlEncodedFormEntity uefEntity;try {uefEntity = new UrlEncodedFormEntity(formparams, "UTF-8");httppost.setEntity(uefEntity);System.out.println("executing request " + httppost.getURI());CloseableHttpResponse response = httpclient.execute(httppost);try {HttpEntity entity = response.getEntity();if (entity != null) {System.out.println("--------------------------------------");System.out.println("Response content: " + EntityUtils.toString(entity, "UTF-8"));System.out.println("--------------------------------------");}} finally {response.close();}} catch (ClientProtocolException e) {e.printStackTrace();} catch (UnsupportedEncodingException e1) {e1.printStackTrace();} catch (IOException e) {e.printStackTrace();} finally {// 关闭连接,释放资源  try {httpclient.close();} catch (IOException e) {e.printStackTrace();}}}/** * 发送 post请求访问本地应用并根据传递参数不同返回不同结果 */public void post() {// 创建默认的httpClient实例.  CloseableHttpClient httpclient = HttpClients.createDefault();// 创建httppost  HttpPost httppost = new HttpPost("http://localhost:8080/myDemo/Ajax/serivceJ.action");// 创建参数队列  List<namevaluepair> formparams = new ArrayList<namevaluepair>();formparams.add(new BasicNameValuePair("type", "house"));UrlEncodedFormEntity uefEntity;try {uefEntity = new UrlEncodedFormEntity(formparams, "UTF-8");httppost.setEntity(uefEntity);System.out.println("executing request " + httppost.getURI());CloseableHttpResponse response = httpclient.execute(httppost);try {HttpEntity entity = response.getEntity();if (entity != null) {System.out.println("--------------------------------------");System.out.println("Response content: " + EntityUtils.toString(entity, "UTF-8"));System.out.println("--------------------------------------");}} finally {response.close();}} catch (ClientProtocolException e) {e.printStackTrace();} catch (UnsupportedEncodingException e1) {e1.printStackTrace();} catch (IOException e) {e.printStackTrace();} finally {// 关闭连接,释放资源  try {httpclient.close();} catch (IOException e) {e.printStackTrace();}}}/** * 发送 get请求 */public void get() {CloseableHttpClient httpclient = HttpClients.createDefault();try {// 创建httpget.  HttpGet httpget = new HttpGet("http://www.baidu.com/");System.out.println("executing request " + httpget.getURI());// 执行get请求.  CloseableHttpResponse response = httpclient.execute(httpget);try {// 获取响应实体  HttpEntity entity = response.getEntity();System.out.println("--------------------------------------");// 打印响应状态  System.out.println(response.getStatusLine());if (entity != null) {// 打印响应内容长度  System.out.println("Response content length: " + entity.getContentLength());// 打印响应内容  System.out.println("Response content: " + EntityUtils.toString(entity));}System.out.println("------------------------------------");} finally {response.close();}} catch (ClientProtocolException e) {e.printStackTrace();} catch (ParseException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();} finally {// 关闭连接,释放资源  try {httpclient.close();} catch (IOException e) {e.printStackTrace();}}}/** * 上传文件 */public void upload() {CloseableHttpClient httpclient = HttpClients.createDefault();try {HttpPost httppost = new HttpPost("http://localhost:8080/myDemo/Ajax/serivceFile.action");FileBody bin = new FileBody(new File("F:\\image\\sendpix0.jpg"));StringBody comment = new StringBody("A binary file of some kind", ContentType.TEXT_PLAIN);HttpEntity reqEntity = MultipartEntityBuilder.create().addPart("bin", bin).addPart("comment", comment).build();httppost.setEntity(reqEntity);System.out.println("executing request " + httppost.getRequestLine());CloseableHttpResponse response = httpclient.execute(httppost);try {System.out.println("----------------------------------------");System.out.println(response.getStatusLine());HttpEntity resEntity = response.getEntity();if (resEntity != null) {System.out.println("Response content length: " + resEntity.getContentLength());}EntityUtils.consume(resEntity);} finally {response.close();}} catch (ClientProtocolException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();} finally {try {httpclient.close();} catch (IOException e) {e.printStackTrace();}}}}</namevaluepair></namevaluepair></namevaluepair></namevaluepair>

本实例是采用HttpClient4.3最新版本。该版本与之前的代码写法风格相差较大，大家多留意下。

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